Rotary pump



June 17, 1941. w w, DAVlDsON 2,246,272v

ROTARY PUMP Filed Aug. 4, 1940 5 Sheets-Sheet l INVENT OR.

rrys.

June 17,1941. w w, DAVIDSON 2,246,272

- ROTARY PUMP Filed Aug. 4,- 1940 v s Sheets-Sheet 2 June 1 1941. I w. w. DAV|DSON 2,246,272

INVENTOR.

June 17, 194] w. w. DAVIDSON 2,246,272

ROTARY PUMP I v I Filed Aug. 4, 1940 5 Shet's-Sheet 5 7 gum 1 INVENTOR.

Patented June 17, 1941 Nl'iED STATES PATENT, OFFICE 2,246,272 ROTARY PUMP William Ward Davidson, Evanston, Ill.

Application August 4, 1940, Serial No. 351,359

21 Claims.

This invention relates to rotary pumps of the planetary type, that is, pumps in which a piston member has rotary movement with respect to a stationary member to produce a pumping action. The principal object of this invention is to provide a pump of this type whichhas exceptional efiicicncy and can be made at costs that are competitive with the present commercial forms of rotary and reciprocating pumps.

Further and other objects andadvantages will become apparent as the disclosure proceeds and the description is read in conjunction with the accompanying drawings, in which Fig. 1 is a vertical, sectional view showing a preferred form of the invention;

Fig. 2 is a horizontal, sectional view taken on the line 2-2 of Fig. 1;

Figs. 3,-4and 5 are diagrammatic views showing successive positions of the piston member at 90 intervals in the pumpcycle;

Fig. 6 is a horizontal, sectional view taken on the line 66 of Fig. 1;

Fig. 7 is a vertical, sectional view taken on the line 'l'| of Fig. 6 and showing particularly the intake valve arrangement;

the lower cylinder head, the partition blade be- 1 ing shown in dotted lines;

Fig. 12 is a perspective view of the driver sleeve;

-Fig. 13 shows the piston member with its integrally formed, upwardly extendingshank which fits within the driver sleeve;

Figf14 is a perspective view of the rocker for the blade;

Fig. 15 shows the partition blade;

Fig. 16- is a vertical, sectional view showing a modification. of the invention in which the piston member is provided with oppositely extending shanks to extend the bearing area;

Fig. 17 illustrates the preferred form of .oil pump 'for use with the structure shown in Fig. 16;

Fig. 18 is ahorizontal, sectional view taken on the line l8-l8 of Fig. 16; and

' Fig. 19 shows another type of oil pump which may be used with either the preferred embodiment of the invention shown in Fig-., 1, or the modified form of the invention shown in Fig. 16.

The disclosure of selected preferred and modified forms of the invention is in compliance with Section 4888 of the Revised Statutes, but it should beunderstood that the appended claims are not to be limited by these specific disclosures unless required by the prior art.

General organization By referring to Fig. 1, it Willbe seen that the planetary pump A is supported by a frame 13 within a dome C, the pump being driven by a motor D, the rotor E of which rotates a driver sleeve F which in turn imparts planetary movement to the pump piston G through a shank H which is in telescopic engagement with the driver sleeve F. A partition blade I divides the pump chamber formed between the upper and lower heads of the pump cylinder into intake and discharge chambers so that each revolution of the piston G discharges gas from the pump and simultaneously draws a new supply of gas into the pump for compression.

Main pump assembly I The main pump assembly (Fig. 1) consists of a stationary cylinder ring 20 preferably of nickel 4 iron, to which upper and lower cylinder'heads 2i and 22 respectively, are secured by dowels 23 and stud bolts 24. The upper cylinder head 2| is integrally formed with a support frame B and preferably ribs 25 'are provided to reinforce the connection between the cylinder head and the frame. The upper portion 26 of the cylinder head 2| receives a steel bushing 21 with a drive fit,'

. lowerface of the motor rotor E, and the cap ing connection be established between the motor rotor E and the driver sleeve F.

The driver sleeve F is eccentrically bored to F and cylinder ring 20 are concentric to each' other, but eccentric to the piston G and shank r the heads 2| and 22, and is then forced inward TH. It is, therefore, obvious that when the driver sleeve F is rotated by the motor rotor E, the shank I-I partakes of a circular movement which moves the pistonaround the inner circumference 35 of the cylinder ring 20, as best shown in Figs. 2-5 inclusive. It will be noted that the point of tangency, generally indicated at T, moves around the cylinder in a clockwise direction assuming the motor is driven in that direction when looking down upon the pump.

The blade I divides the crescent-shaped pump chamber 38 into intake and discharge compartments of constantly varying size, that portion of the pump chamber lying clockwise between the blade I and the point of tangency being themtake chamber 31 and that portion lying clockwise between the point of tangency andthe blade I being the discharge chamber 38. The blade isrigidly secured to the cylinder ring 20 and the associated heads 2t and 22, and has rocking and sliding engagement with the piston G by means of a rocker 39. This arrangement is not only highly eifective and desirable for partitioning the pump chamber, but it alsoholds the piston G against substantial rotary movement about its own axis, and as a result, reduces the wear between the piston and the cylinder ring.

The driver sleeve F, cylinder heads 2| and 22, cylinder ring 20, and rocker 39 are preferably made of nickel iron, while the bushing 21, piston G, shank H and blade I are preferably of ma chine or tool steel, so that in all instances where two surfaces are in sliding engagement with each other, one of the surfaces is a hard steel, and the other a softer nickel iron.

The lower cylinder head 22 is provided with a protuberance 40 having a bore 4| which is concentric with the outer surface of the driver.

sleeve F and the inner surface of the cylinder ring 20. A plug 42 of nickel iron is drive fitted into the bore 4| and the cap 43 of the plug constitutes a stationary member which forms one element of an oil pump generally designated 44 (Fig. 6).

tion of the blade I is in close sliding engagement with the cap 43 (see Fig. 6) and as a result, the crescent-shaped space between the cap 43 and the walls of the counterbore 45 form a pump chamber for oil, the discharge portion of the chamber being indicated at 41 and the intake portion being indicated at 48.

The blade I is rigidly clamped to the cylinder ring 20 and the associated cylinder heads so that it is effectively sealed by this rigid connection on three sides. The cylinder ring 20 ispreferably split vertically to provide opposed portions 49 and 50; and capscrews which pass through enlarged openings 52 in the blade, clamp the blade in place. Since it is important for the lower extension 46 on the blade to have a sealed fit with the cap 43 of the oil pump plug 42, the blade is first mounted loosely between ly until it makes proper engagement with the cap 43, after which the blade screws 5! and head bolts 24 are tightened down to hold the adjustment.

The entire pump assembly is mounted within the dome C after first'drive fitting the motor stator 53 into place against a seat 54 provided in the dome. The pump support frame B is then slid into place until it seats upon a shoulder 55 provided in the dome. A plurality of cap screws 56 securely fasten the frame to the dome.

The collar 30 is preferably provided with a counterweight 51 to balance the eccentricity of the planetary piston G. Being located on the opposite side from the support frame, the pump may be nicely balanced in this way, thus making the pump substantially free from vibration.

Preferably the counterweight is provided with a guide lug 58 which travels within a groove 59 provided in the stationary upper cylinder head 2|. In normal operation of the pump, the guide lug 58 runs free within the groove 59, but should the pump be inverted for any reason, the lug 58' holds the motor rotor E- in place so that return of the pump to normalposition places the pump in immediate readiness ;.for operation. The guide lug, 58, therefore, merely serves to prevent displacement of the parts when the pump is inverted.

The casing C is provided with a fitting, generally designated 60, for receiving gas to be compressed by the pump A. The fitting is held in place on the dome by a cap screw 5|,

In the embodiment of the invention shown in Figs. 1 and 2, the dome is on the low side, that is, it ismaintained at a pressure corresponding to the pressure of the gas prior to compression and the compressed gas is taken from the pump directly to the exterior of the dome. By using a low pressure dome, the pump parts may be kept cooler and forced draft over the compressor dome may be unnecessary. However, it should be understood thatif desired, the pump may be constructed to operate with the dome on the high pressure side and with gas being delivered to the pump directly through a tube.

When the pump is operated on a low pressure dome, as shown in Figs. 1 and 2, the gas intake tube 52 is open to the dome and a similar tube 53 takes the gas from the dome and delivers it through a fitting 64, screen 65, intake valve generally designated 66, and intake ports 61 to the intake chamber 31 of the main pump. The fitting 64 is threaded into the lower cylinder head 22 and the screen as is located within a chamber 38 provided in the lower head. (Fig. 7). The intake valve 86 is located within a chamber 59 provided in the ring 20 and communicates with the head chamber 68 through a passage 10. A disk valve member II is held iin,- place on a valve seat 12 by a steel ball 13 which is free to travel within a guideway I4 provided in the valve housing 15. The housing is yieldingly urged against the lower cylinder head 22 by a spring 15, although if desired, it may be rigidly held within the ring 20 by a drive fit. The housing has a plurality of openings 11 through which gas entering the housing through the valve Il may pass 10 the chamber 69 and thence through the ports 61 into the intake chamber 31. The weight of the ball 13 is sufficient' to keep the valve closed at all times except when the pump is drawing gas into the chamber 31.

IM and I02 on the lower and upper faces, respec- As the point of tangency sweeps around the cylinder ring 20, the gas in the discharge chamber 38 is compressed until it reaches a pressure which opens the discharge valve generally desig nated I8. which is sealed against the flat Wall 80 of the cylinder ring by means of a forked lever 8|. The lever BI is pivoted about one of the stud bolts 24 and has a forked end 82 (Figs. 2 and 8) which straddles the discharge elbow 83 and rests upon shoulders 84 to force the housing I9 into 'firm engagement with the wall 80 when the lever is rocked about its pivot 24 by a set screw 05,

The valve member 86 of the discharge valve is held against its seat Bl bya spring 88 which is selected with proper tension to open the valve at some given discharge pressuredifferential.

The discharge chamber 38 of the pump A com- This valve comprises a housing I9 municates with the interior of the valve housingv I 19 through a passageway 89 and a tube 90 de-v livers the compressed gas to a fitting 9I which in turn is connected to suitable auxiliary equipment.

When the dome is operated on the high side of the pumlm. the tube 62 is connected directly to the nipple 64 of the intake valve and the tube 90 associated with the discharge valve is placed in communication withtheinterior of the dome, as is also the tube associated with the system, particularly when the dome is on the low side. This is true because the oil in a low side dome is under substantially constant pressure, whereas the pressure in the workchamber of the pump depends upon theloadwhich'the pump is carrying, and hence varies within, wide I limits. An oil pump, therefore, which delivers an adequate pressure for lubrication and sealing of the pump parts when the pump is operating under a given head pressure, may be totally inadequate or unsatisfactory when the head pres-- r sure is increased to some larger amount.

Even in pumps using a high side dome the use of the proper type of oil pump is highly important, and I, therefore, providea lubricating and sealing system which is positive in its action and is capable of properly oiling and sealing the various pump surfaces regardless of the variations in head pressure on the main pump. This oiling system preferably includes a pump of the positive displacement type, or at least a pump which is capable of delivering oil for more than 50% of the pump cycle.

The dome C has an oil reservoir 92 in the bot-' tom of the dome, the latter being closed by a bottom cover plate 93 which is secured to flanges 94 of the dome by a plurality of cap screws 95. An oil intake pipe 96 (Fig, 7) fitted at its end with a strainer 97 conducts oil from the reservoir to the counterbore, 4| in the lower cylinder head 22. A passageway 98 through the plug 42 connects the oil space below the plug with the intake chamber 48 of the oil pump 44. As the piston G partakes of planetary movement, the point of tangency T between the plug cap 43 of the oil pump and the counterbore 45 in the piston G moves about the cap 43 in a clockwise direction (Fig. 6) thus causing oil to be forced from the chamber 41 through a discharge passage 99 in the plug 42, and through another discharge passage I00 which connects with arcuate grooves and sealed.

tively of the piston G, the two grooves being joined together at their ends by vertical bores I03 and I04;

will be moved through the various discharge passages for each cycle of the pump and adequate lubrication and sealing of the piston faces is thereby assured regardless of the head pressure on the main pump. The pump '44 will therefore deliver oil to the working clearances of the main pump at pressures well in excess of the work' pressure in the main pump chamber.

A vertical bore I05 which extends through the piston G and into the piston shank H, has an enlarged mouthIilB which communicates at all times with the discharge passage 99 in the stationary cap 43 of the oil pump even though there is relative planetary motion between the piston Gand the cap 43. Oil is, therefore, continuously delivered throughout substantially the entire pump cycle to the vertical bore I05 and supplied I under continuous pressure in excess of work chamberpressure to the various work surfaces and bearing surfaces which 'mustbe lubricated For example, a passageway I01 extends horizontally from the bore I05 to a groove I08 so that the rocker 39 may be properly lubricated andseaIed. Also, a passage I09.ex-

tends laterally from the bore I05 to a relieved portion IIO in the piston shank H to permit oil to be forced upwardly and downwardly along the shank bearing surfaces. A passage way HI communicates with the. relieved portion M2 on the outer face'of the driver sleeve F and. this in turn communicates with a horizontal passage H3 in the support frame Bwhich leads to an adjustable oil pressure relief valve II4 which a may be adjusted to provide the desired head pressure'in the oiling and lubricating system. Theoil pump may be made smaller or larger to suit different head pressure conditions for which the main pump may be designed. Obviously, if

the head pressure is too great, it will set up a back pressure that will detract from the overall efliciency of the pump, whereas if it is too small, the bearing surfaces and work surfaces in the pump chamber will not be adequately sealed against leakage.

It should be understood that the lubricating and sealing system which has been described has equal applicability to a-pump which is housed within a dome that is on the high side of the main pump, although in such instances, other types of oil pumps such, for example, as gear pumps, centrifugal pumps, and other pumps which deliver oil for more than 50% of the operating cycle for the main pump, may be used with probably more effectiveness than would be the case were these oil pumps used with a low side dome.

In order to prevent undesirable oil pressures from being set up in the space H5 between the top of the piston shank H and the closure head 32 for the driver sleeve'F, which pressure would tary piston I35.

I I1 is provided through the washer 34 so that the oil pressure within the chamber II5 will be substantially equal to dome pressure. Obviously, the oil escaping through the-orifice II1, as well as all other oil which escapes from the bearings, or the relief passage II3, will fall to the oil reservoir 92 for re-use.

The motor leads IIB into the dome are preferably carried through the dome by a connector generally designated II9, as best shown in Fig. 2. The connector consists of a copper rod I having an enlarged central portion I 2I backed on both sides by Duprene washers I22 which are clamped against the enlarged portion I2I by fiber insulators I23 which fit within a housing I24 welded onto the dome and closed by a threaded cap I25. The advantage of this arrangement is that should any leak develop through the connector, the cap I25 may be removed to replace the outer Duprene washer I22, this being accomplished without opening up the base 93 of the dome.

Modified formFigs. 16 through. 19, inclusive In the modified form of the invention shown in Figs. 16 to 19 inclusive, a somewhat different arrangement is provided for driving the piston member while still retaining the advantages of having bearing areas for taking the force of compression which are greater in width than the width of the pump chamber and while retaining also the advantages of adequate lubrication and gas sealing.

Referring to Fig. 16, the pump assembly is mounted as before on a frame B within the dome C, but in this instance, the upper and lower cylinder heads I and I3I respectively arebored as shown at I32 and I33 respectively, to receive the oppositely extending shanks I34 of the plane- The pump chamber I36 consists as before, of the crescent-shaped space that is defined by the upper and lower cylinder heads I30 and I3I, the outer circumference of the piston I and the inner circumference of the cylinder ring I31. A partition blade I38 divides the pump chamber I36 into intake and discharge sides and is clamped in place within the cylinder ring by cap screws I39 and is similarly sealed against the top and bottom cylinder walls by the clamping action ofthe studs I40. The blade cooperates with a rocker I4I provided in the piston, as best shown in Figs. 16 and 18.

.The piston is driven by a crank or eccentric I42 provided on the drive shaft I43 which is rigidly connected to the motor rotor I44. It will be noticed that the force of compression is distributed over the bearing area between the piston I35, with its extension shanks I34, and the shaft I 43 and the work chamber I49 of the oil pump is divided into intake and discharge chambers by a blade I50 rigidly fixed by a pin I5I to a piston I46 and having rocking and sliding engagement with the stationary head I3I through a rocker I52. The oil intake into the work space I49 is indicated at I53 and the discharge for the oil pump is through a downwardly extending passageway I54 which communicates with an open space I55 formed below the shaft I43 in the bottom plate I56 which attaches to the lower face of the lower cylinder head I3I.

Oil under pressure is transmitted through the space I55 to a vertical bore I51 in the shaft I43 from whence the oil is distributed to the piston bearing through channel I58; to the rocker bearing through channel I59; to the face grooves I60 and I 6| in the piston through groove I62 and passages I63; and to the upper andlower shaft bearings through passages I64 and I65, respectively. An oil relief passage I66 is provided to prevent excess oil pressures from setting up undesirable back pressures which would have a tendency to increase the power required for op erating the pump.

While the pump structure shown in Figs, 16 and 17 is preferred, another satisfactory type of pump is illustrated in Fig. 19 at I61. This pump is of the centrifugal type and consists of a rocrank I42, this hearing being considerably wider cendof the drive shaft.

In this instance, the -oil pump comprises a piston member I46 which is mounted in eccentric tangential relation to a bore I41 in the lower face of the cylinder head I3I. The planetary movement of the piston I46 is imparted by a crank arm I 48 at the lower end of the drive tor having a plurality of radially extending vanes I68, which take oil introduced into the pump centrally by an intake passage I69 and drive it outwardly by centrifugal action into the enlarged portion I10 of the cylindrical recess provided in the lower face of the cylinder head I 3|. The discharge passage for the oil pump is indicated at HI, and it communicates with the vertical bore I51 for distribution of oil to vital places, as shown in Fig, 16.

The rotor of the oil pump is rigidly attached to the'drive shaft I43 by a screw I12 or other suitable means.

Preferably small oil relief passages I13 are provided in the heads I30 and m to prevent undesirable oil pressures from being built upin the bores I32 and I33.

It should be noted that all forms of the oil pumps herein shown and described are characterized by the factthat they deliver oil for more than 50% of their operating cycle, and by the further fact that they do not require the use of complicated valve structure, as is the case with reciprocating types of pumps.

Preferably the oil pump I45 shown in Figs. 16 and 17 is out of phase with the main pump, i. e. the oil pump cycle is 90 in advance of the main pump. cycle. The reason for this is to have the greatest volume of oil delivery coincide with the last of the main pump cycle, when the work chamber pressure is highest and maxi mum sealing of the clearance spaces is required. The greatest volumetric delivery of oil from the pump I45 occurs as the point of tangency for the piston I46 moves clockwise from the position X to the position Y (Fig. 17), and for this maximum delivery to occur while the point of tangency forv the main pump moves clockwise from the point X to Y' (Fig. 18) it is necessary to have the crank I48 of the oil pump 90 in advance of the crank I42 of the main pump.

There is even some advantage when the oil pump is 180 out of phase as shown in the drawings because maximum delivery of oil then coincides with a substantial portion of the maximum pressure stage of the main pump.

To summarize in part some of the advantages of the pump structures which have been described, all of the pump structures are characterized by their ability to be made at relatively low cost, and to perform with outstanding efiiciency. For example, the preferred embodiment of the invention shown in Figs. 1-15 inclusive has undergone tests which indicate that its power factor is far lower than competitive pumps now on the market. This remarkable performance is believed to be due to a combination of several features among which are the followingi (a) The use of a stationary fixed blade in the main pump which is rigidly sealed on three sides by the cylinder ring and the cooperating cylinder heads.

ing sealed fit with the piston for dividing the chamber into intake and discharge stages with closing the ends of the oil pump cylinder to provide a pumping chamber for the oil pump, and a blade carried by one of the oil pump members and engaging the other thereof dividing the oil pump chamber into intake and discharge stages, said oil pump being actuated by the sealing system which delivers oil to all clearance spaces of the pump parts at pressures in excess of work chamber pressure and which preferably includes'oil pumps of the type which are characterized by delivering a stream of oil under pressure for more than of the pump cycle and which do not require complicated valve structures.

I claim:

1. In a compressor, pump elements including a stationary headed-cylinder comprising an outer ring and end walls, and a piston within the cylinder mounted in eccentric tangential relation to the outer ring to form a crescent-shaped pump chamber, a blade dividing the chamber into intake and discharge stages, said blade being rigid with the outer ring and having a sealed fit with the end walls and ring, and a pivotally sliding sealed fit with the piston, 'inlet and outlet ports on opposite sides of the blade, driving means for moving the piston within the cylinder to produce a pumping action in the pump chamber, an auxiliary pump for delivering oil at pressures in excess of work pressuresin the main pump chamber for more than one-half of the pumping cycle of the main pump including as pump members'a cylinder formed in a recess in one of said elements and a piston in eccentric tangential relationship thereto, a blade for the auxiliary pump carried by one of the auxiliary pump members and engaging the other thereof dividing said recess into intake and discharge sections, said auxiliary pump being actuated with the main pump by the driving means therefor to produce a pumping action with relative movement between the piston and cylinder of the auxiliary pump, an intake for the auxiliary pump adapted to supply a lubricant thereto, and discharge passage means for delivering the lubricant from the auxiliary pump to the clearances between the elements of the main pump.

2. In a device of the class described, a mainpump comprising a stationary cylinder having heads rigidly fixed thereto and a piston within the cylinder mounted in eccentric tangential relation to form a pump chamber, a blade rigid with the cylinder and having a sealed fit with the end walls and cylinder, and a pivotally sliddriving means for the main pump to produce a pumping action with relative movement between the pistonand cylinder of the oil pump, an intake for the oil pump adapted to supply lubricant thereto, and discharge passage means for delivering the lubricant from the oil pump to the working clearances of the main pump.

3. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigid with one of said members and defining with both members a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, inlet and outlet ports on opposite sides of the partition, one of said pump members being stationary and the other movable, driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pumping chamber, and an auxiliary pump for supplying lubricant under pressure in excess of that within the pump chamber of the main pump to the working clearances thereof, said auxiliary pump comprising as pump members a cylinder and a piston mounted in eccentric tangential relation thereto, means for closing the ends of the cylinder to form with the cylinderand piston an auxiliary pump chamber, and a blade for the auxiliary pump constituting an integral part of the partition for the main pump and carried 'by one of the auxiliary pump members and engaging the other thereof to divide the auxiliary pump chamber into intake and discharge sections, said auxiliary pump being actuated with the main pump by said driving means to produce a pumping action with relative movement between the piston and cylinder of the auxiliary pump, an oil intake to the auxiliary pump,

and means for delivering oil from the auxiliary pump to the working clearances of the main pump.

4. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation,

end plates rigid with one of said members and defining with both members a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of saidv pump members being stationary and the other movable, inlet and outlet ports on opposite sides of the partition, driving means, for causing the movable pump member to move relative to the stationary member to produce a pumping action Within the pumping chamher, and an auxiliary pump having inlet and discharge passages for supplying oil at pressures in ,excess of work pressuresin th main pump chambar to the working clearances of the main pump, said auxiliary pump being of the rotary type and being characterized by its ability to deliver oil at said pressures to said clearances for more than half of the pumping cycle of the main pump.

5. In a device of the class described, a main pump comprising a stationary cylinder, a piston therein mounted in eccentric tangential relation, and plates rigid with the cylinder to define with the cylinder and piston a main pump champer, a partition blade fixed to the cylinder and end plates and having rocking and sliding engagement with the piston, inlet and outlet ports on opposite sides of the blade, a rigid shank on the piston extending laterally beyond the inner pump chamber face of the adjacent end plate to provide a bearing surface of ample lengthto directly take the force of compression, driving means engaging said bearing surface'for moving the piston within the cylinder to produce a pumping action in the pump chamber, and an oil pump actuated by said driving means for delivering oil under pressure in excess of that within the main pump chamber to the working clearances of the main pump, said oil pump being of the rotary type and being characterized by its ability to deliver oil to said-working clearances at said pressures for more than half of the pumping cycle for the main pump.

6. In a device of the class described, a main pump comprising a stationary cylinder, a piston therein mounted in eccentric tangential relation, end plates rigid with the cylinder to define with the cylinder and pistonv a main pump chamber, a partition blade fixed to the cylinder and end plates and having rocking and sliding engagement with the piston, inlet and outlet ports on opposite sides of the blade, a rigid shank on the piston extending laterally beyond the inner pump chamber face of the adjacent end plate to provide a bearing surface of ample length to directly take the force of compression, driving means engaging said bearing surface for moving the piston within the cylinder to produce a pumping action in the pump chamber, and an oil pump actuated by said driving means for delivering oil under pressure in excess of that within the main pump chamber to the working clearances of the main,

pump, said oil pump being of the rotary type and being characterized by its ability to deliver oil to said working clearances at said pressures for more than half of the pumping cycle for the main pump, said oil pump being further characterized by having intake and discharge stages which are in open communication with intake and discharg passages leading to the oil pump.

7. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form with the other a pump chamber, a

' partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of said pump members being stationary and the other movable, inlet and outlet ports on opposite sides of the partition, driving means for causing the movable pump member to move relative to the stationary pump member to produce a pumping action within the pump chamber, and bearing means including a shank rigid with the movable pump member and extending outside of the space between the end plates whereby ample support may be provided for the shank to directly take the force of compression, said bearing means having a total length which is substantially in excess of the width of the pump chamber, and an auxiliary pump for delivering oil at pressures in excess of work pressures in th main pump chamber for more than one-half of the pumping cycle of the main pump for supplying lubricant under pressure to the working clearances of the'main pump, said auxiliary pump including as pump members a cylinder, a piston in eccentric tangential relationship thereto and a blade for the auxiliary pump carried by one of the auxiliary pump members and engaging the other thereof dividing the auxiliary pump chamber into intake and discharge sections, said auxiliary pump being actuated with the main pump by said driving means to produce a pumping action with relative movement between the piston cylinder and the auxiliary pump, an intake for supplying lubricant to the auxiliary pump, and discharge passage means for delivering the lubricant from the auxiliary pump to the working clearances of the main pump.

8. In a rotary pump, a gas tight dome, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigid with one of said members and defining with both members a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of said pump members being stationary and the other movable, inlet and outlet ports on opposite sides of the partition, driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pumping chamber, and an auxiliary pump for supplying lubricant under pressure in excess of that within the pump chamber of the main pump to the working clearances thereof,

said auxiliary pump comprising as pump members a cylinder and a piston mounted in eccentric tangential relation thereto, means for closing the ends of the cylinder to form with the cylinder and piston an auxiliary pump chamber, and a blade for the auxiliary pump carried by one of the auxiliary pump members and engaging the other thereof to divide the auxiliary pump chamber into intake and discharge sections, said auxiliary pump being, actuated with the main pump by said driving means to produce a pump-. ing action with relative movement between the piston and cylinder of the auxiliary pump, an oil intake to the auxiliary pump, and mean for delivering oil from the auxiliary pump to the working clearances of the main pump, said dome being in open communication with the intake stage of the main pump.

9. In a rotary pump, a main pump comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, heads rigidly ilxed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber into intake and discharge stages, said blade having rocking and sliding engagement with the piston, inlet and outlet ports on opposite sides of the blade, driving means for moving the piston relaand an auxiliary pump associated with the main pump for delivering oil at pressures in excess 01 working pressure within the main pump chamber to lubricate and seal the Working clearances of the main pump, said auxiliary pump including ton member mounted therein in eccentric tangential relation, one of said members being rigid I with the stationary cylinder of the main pump, and the other of said members being rigid with the piston of the main pump, means for closing the ends of the auxiliary pump cylinder to form a Work chamber, means dividing the auxiliary pump work chamber into intake and discharge stages, an intake for supplying oil to the auxiliary pump, discharge means for delivering oil from the auxiliary pump to the working clearances of the main pump, said auxiliary pump being actuated by the driving means for the main pump.

10. In a rotary pump, a main pump comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, heads rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the mainpump chamber into intake and discharge stages, said blade having rocking and sliding engagement with the piston, inlet and outlet ports on opposite sides of the blade, means for impartinga planetary movement to the piston member whereby a pumping action is produced within the pump chamber, saidmeans including a laterally extending shank rigid with the piston and a driver in telescopic engagement with the shank and having its axis of rotation eccentric to the axis of the shank, and an auxiliary pump associated with the main pump for delivering oil under pressure in excess of main pump head pressure to the working clearances of the main pump, said auxiliary pump including as pump members a cylinder member and a piston member mounted therein in eccentric tangential relation, one of said members being rigid with the stationary cylinder of the main pump, and the other being rigid with the piston of the main pump, means for closing the ends of the auxiliary pump cylinder to form a work chamber, means dividing the auxiliary pump chamber into intake and discharge stages, an intake for supplying lubricant to the auxiliary pump, discharge means for delivering lubricant from the auxiliary pump to the working clearances of the main pump, and means for actuating the auxiliary pump by the driving means for the main pump.

11. In a rotary pump, a main pump comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, head rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber into intake and discharge stages, said blade having rocking and sliding engagement with the piston, inlet and outlet ports on opposite sides of the blade, driving means for imparting to the piston a planetary movement to produce a pumping action in the pump chamber, said driving means including a shank rigid with the piston and projecting laterally to one side of the'pump, a driver sleeve eccentrically telescoped over the shank and members a cylinder memberand a piston mem ber mounted therein in'eccentric tangential relation, one of said members being rigid withthe stationary cylinder ofthe main pump, and the other being rigid with the piston of the main pump, means for closing the ends of the auxiliary pump cylinder to form a work chamber, means dividing the auxiliary pump chamber into intake and discharge stages, an intake for supplying lubricant to the auxiliary pump, discharge means for delivering lubricant from the auxiliary pump to the working clearances of the main pump, and means for actuating the auxiliary pump by the driving means for the main pump.

12. In a rotary pump, a main pump comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, heads rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber into intake and discharge stages, inlet and outlet ports on opposite sides of the blade, said blade having rocking and sliding engagement with the piston, driving means for imparting to thepiston a planetary movement to produce a pumping action in the pump chamber, said driving means including a shank rigid with the piston and projecting laterally to one side of the pump, a' /driver sleeve eccentrically telescoped over the shank and adapted when rotated about its own center to impartto the piston through the shank a planetary motion within the cylinder to produce a pumping action, and an auxiliary pump associated with the main pump for delivering oil at pressures in excess of working pressure within the main pump chamber to lubricate and seal the working clearances of the main pump, said auxiliary pump including a cylindrical recess. in the face of the piston remote from the shank, a piston rigid with the stationary cylinder of the main pump mounted in eccentric tangential relation to the cylindrical recess, means for closing the ends of the auxiliary pump to 'form a work chamber, an intake for supplying lubricant to the auxiliary pump, discharge means for delivering oil from the auxiliary pump to the working clearances of the main pump, and means for dividing the auxiliary pump chamber into intake and discharge stages communicating with said oil intake and discharge means respectively whereby planetary movement of the main pump piston within the'main pump cylinder will produce a pumping action within the auxiliary pump for delivering oil through said auxiliary tion, means for producing relative movement between the pump members to produce a pumping action within the pump chamber, and an auxiliary pump operatively associated with the main pump, said auxiliary pump including as pump pump piston, inlet and outlet ports on opposite I sides of said dividing means and means for adjustably positioning the main pump partition in proper running relation to the auxiliary pump piston and thereafter locking said partition to the end plates of the main pump and the main pump member to which said end plates are secured.

14. In a rotary pump, a gas-tight dome, a motor stator mounted within the dome, a main pump comprising a stationary cylinder, a piston mounted therein. in eccentric tangential relation, heads rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber in-to intake and discharge stages, said blade having rocking and .sliding engagement with the piston, inlet andoutlet ports on opposite sides of the blade, driving means for imparting to the .piston a planetary movement. to produce a pumping action in the pump chamber, said driving means including-a shank rigid with the piston and projecting laterally. to one side of the pump, a driver sleeve eocentrically -telescoped over the shank and adapted when rotated about its own center to impart to the piston through the shank a planetary motion within the cylinder to produce a pumping'action, a motor rotor carried by the driver sleeve, a bearing on one of the cylinder heads overlapping the telescopic engagement of the driver sleeve and shank, a support 'frame rigidly attached to saidcylinderhead bearing for supporting the entire pump assembly within the dome, and-an auxiliary pump associated with the main pump for delivering oil under pressure in excess of main pump head pressure to the working clearbeing rigid with the stationary cylinder of themain pump and the other being rigid with the piston of the main pump, means for closing the ends of the auxiliary pump cylinder to form a work chamber, means dividing the auxiliary pump chamber into intake and discharge stages, an intake for supplying lubricant to the auxiliary pump, discharge means for delivering lubricant from the auxiliary pump to the working clearances of the main pump, and means for actuating the auxiliary pump by the driving means for the main pump,

15. In a rotary pump, a main pump compris- 4 ing a stationary cylinder, a piston mounted her, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber into intake and discharge stages, said blade having rocking 'and sliding engagement with. the piston, inlet and outlet ports on opposite sides of the blade, driving means for moving the pis- 1 ton relative .to the cylinder to produce a pumping action within the pump chamber, said driving means including a shaft extending through the piston and having an eccentric in telescopic engagement with a central bearing on the piston, said bearing including a laterally projecting shank on the piston extending beyond one of the inner faces of the cylinder heads and providing a bearing surface having greater axial length than the Width of the pump chamber, and an auxiliary pump associated with the main pump for delivering oil under pressure to lubricate and seal the working clearances of the main pump, said auxiliary pump being of the rotary type and characterized by its ability to supply lubricant to said working clearances for more than half of the main pump cycle.

16. In a rotary pump, a main pump comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, heads rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividing the main pump chamber into intake and discharge stages, said blade having rocking and sliding engagement with the piston inlet and outlet ports on opposite sides of the blade, driving means for moving the piston relative to the cylinder to produce a pumping action within the pumpchamber, said driving means including a shaft extending through the iston and having an eccentric in telescopic engagement with a central bearing on the piston, sai'd bearing including a laterally projecting shank on the piston extending beyond one of the inner faces of the cylinder heads and providing a bearing surface having greater axial length than the width of the pump chamber, and an auxiliary pump associated withthe main pump for. delivering oil under pressure in excess of main pump head pressure to lubricate and seal the working clearances of the main pump, said auxiliary pump including as pump members a cylinder member and a piston member mounted in eccentric tangential relation, means for closing the ends of the auxiliary pump cylinder to form a work chamber, means for divid ing the auxiliary pump chamber into intake and discharge stages, and means including the drive shaft for imparting relative movement between the cylinder and the piston of the auxiliary pump to produce a pumping action within the auxiliary pump chamberyan intake for supplying lubricant to the auxiliary pump, and discharge means for delivering oil from the auxiliary pump to the working clearances of the main pump.

17. In a rotary pump, a main pump 'comprising a stationary cylinder, a piston mounted therein in eccentric tangential relation, heads rigidly fixed to the cylinder and defining with the cylinder and the piston a main pump chamber, a blade rigidly attached to the cylinder and the heads for dividin the main pump chamber into intake and discharge stages, said blade having rocking and sliding engagement with the pis- -ton, inlet and outlet ports on opposite sides of the blade, driving means for moving the piston relative to the cylinder to produce a pumping action within the pump chamber, said driving means including a. shaft extending through the piston and having an eccentric in telescopic engagement with a central bearing on the piston, said bearing including a laterally projecting shank on th piston extending beyond one of the inner faces of the cylinder heads and providing .a bearing surface havinggreater axial length than the width of the pump chamber,

and an auxiliary pump associated with the main pump for delivering oil under pressure in excess of main pump head pressure to lubricate and seal the working clearances of the main pump, said auxiliary pump including as pump members a cylinder member and a piston member mounted in eccentric tangential relation,

means for closing the ends of the auxiliary pump cylinder to form a work chamber, means for dividing tne auxiliary pump chamber into intake and discharge stages, and means' including the drive shaft for imparting relative movement between the cylinder and the piston of r the auxiliary pump to produce a pumping action within the auxiliary pump chamber, an intake for supplyinglubricant to the auxiliary pump, and discharge means for delivering oil from the auxiliary pump to the working clearances of the main pump, the auxiliary pump having a phase relationship to the main pump which causes the greatest volume of oil to be ,8

delivered to the working clearances of the main pump when the pressure in the main pump chamber is highest. 1

18. In a rotary pump, pump members including a hollow cylindrical member, a piston mem-- ber mounted therein in eccentric tangential relation therewith, end plates rigidly secured. to one of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member a to which they'are secured, said partition being immovably fixed relatively thereto, one of said, pump members being stationary and the other movable, driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pump chamber, said driving means including a shaft having an eccentric, said movchamber, and means for journaling the drive shaft on both sides of the eccentric.

- 20. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential rela tion therewith, end plates rigidly secured to one of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of said pump members being stationary and the other movable,

driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within; the pump chamber, said driving meansincluding a shaft having an eccentric, said movable pump member having an axial internal bearing surface for the eccentric, a hollow shank rigid with the movable pump member and projecting outwardly through one of the end plates to provide an extension of said internal bearing surface, the total length of the bearing surface in en'- gagement with the eccentric being substantially in excess of the width of the pump chamber, and an oil pump driven by the same power that drives the main pump and having an inlet port and one or more discharge passages leading to at least some of the working clearances of the main pump, said oil pump being characterized by its ability to supply oil to said Working clearances at sufficiently high pressures to effectively seal the main pumpagainst leakage of the fluid being operated on.

21. In a rotary pump, .pump members including a hollow cylindrical member, a piston memable pump member having an axial internal bearing surface for the eccentric, a hollow shank rigid with the movable pump member and projecting outwardly through one of the end plates to provide an extension of said internal bearing surface, the total length of the bearing surface in engagement with the eccentric being substantially in excess of the width of the pump chamber.

19. In a rotary pump, pump members including a hollow cylindrical member, a piston memf ber mounted therein in eccentric tangential relation therewith, end plates rigidly secured to one, of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of said pump members being stationary and the other movable, driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pump chamber, said driving means including an axial internal bearing surface in the movable pump member, a drive shaft extending through the movable pump member and having an eccentrio in engagement with said bearing surface, a

- hollow shank rigid with the movable pump member projecting outwardly through one' of the end plates and providing an extension of the lntemal bearing surface, the total length of the bearing surface in engagement with the eccentric bein substantially in' excess of the width of the pump ber mounted therein in eccentric tangential relation therewith, end plates rigidly secured to one of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relatively thereto, one of said pump mem-. bers being stationary and the other movable,

driving means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pump chamber, said driving means including an axial internal bearing surface in the movable pump member, a drive shaft extending through the movable pump member and having an eccentric in engagement with said bearing surface, a hollow shank rigid with the movable pump member projecting outwardly through one the main pump and having an inlet port and one or more discharge passages leading to at least some of the working clearances of the main pump, said oil pump being characterized by its ability to supply oil to said working clearances at sufiiciently high pressures to effectively seal the main pump against leakage of the fluid being operated on.

4 WILLIAM WARD DAVIDSON. 

